CN205561748U - Electric current range unit - Google Patents

Abstract

The utility model relates to an electric current range unit mainly includes: the signal produces the part, measures metal strip and slip read head in the poor part of two way signal phases, treatment circuit part and the measuring -signal device. Wherein the signal produces the part including the crystal oscillator circuit of the main signal that shakes of production and the phase -locked loop circuit that produces the local oscillator signal. The signal measurement device includes signal transmission and receiving terminal, two metal strips that are parallel to each other and a slidable read head that is used for coupled signal, and one of them strip metal strip is connected with the signal transmission end, and another strip metal strip is connected with the signal reception end, and the metal media is used for conduction and repayment signal. Shake local oscillator signal connection to the mixer circuit of signal and phase -locked loop circuit of owner that the signal produced the part. Above -mentioned electric current range unit has overcome the electromagnetic wave signal and can not transmit the problem of coming the measuring distance on plain conductor.

Description

A kind of electric current range unit

Technical field

This utility model relates to a kind of electric current range unit.

Background technology

At present, the instrument measuring distance is typically according to optics, acoustics and electromagnetic wave principle design, and measures distance The general mode used has two kinds: impulse method and phase method.

Chinese patent CN201510574023.8 proposes a kind of laser short distance distance-finding method, the detailed process of the method For: step one, Laser emission end is fixed optical fibers, and the helically wound formula of optical fibers；Step 2, utilizes with light The Laser emission end measuring targets leading fiber carries out laser ranging, it is thus achieved that length L of the propagation path of laser₂, step 3, will Length L of the propagation path of laser₂Deduct fibre-optic length L₁, it is thus achieved that the distance between Laser emission end and object under test L_true, complete the short distance range finding of laser.But, owing to the spread speed of light is too fast, spread length L of laser₁And L₂It is not easy Measure, cause measurement error big.

Chinese patent CN201210009206.1 patent proposes a kind of tellurometer survey technology, and this is a kind of based on carrier wave tune Many surveys chi microwave phase distance-finding method of principle processed.At measured point, place microwave passive reflector, place micro-in measurement point Ripple diastimeter.Distance measuring signal source first produces dominant frequency distance measuring signal after mixing, power amplifier by launching antenna transmitting, and reflector is by incidence Microwave signal to it is reflected back by former road, and reception antenna receives microwave signal, after LNA, bandpass filtering, mixing, and mirror Phase device is measured reflection and launches signal phase difference ΔΦ 1；This phase contrast to found range from proportional, thus can distance.This survey Being limited by dominant frequency signal wavelength away from scope, though increasing wavelength can expand finding range, but range accuracy can reduce.In order to ensure essence Spending and expand finding range, signal source produces the range finding of auxiliary frequency distance measuring signal again, obtains phase contrast ΔΦ 2, then according to ΔΦ 1 and ΔΦ 2 obtain found range from.This method need to be modulated signal and demodulate, and adds the complexity of circuit, easily produces various Interference.Furthermore, the method needs to place microwave passive reflector at measured point, is not easy to the convenience measured.

Utility model content

A kind of electric current range unit that this utility model provides to solve the problems referred to above, described electric current range unit bag Include: current signal produces part, signal measurement apparatus, mixing and phase discriminator part and process circuit part, described electric current Signal generator divides and includes producing the crystal oscillating circuit of the main signal that shakes and producing the phase-locked loop circuit of local oscillation signal, described signal measurement Device include signal sending end and signal receiving end, two bonding jumpers being parallel to each other and one on described bonding jumper for The slidably read head of coupled signal, wherein a described bonding jumper is connected with described signal sending end, another described bonding jumper Being connected with described signal receiving end, described mixing and phase demodulation part include mixting circuit and phase discriminator, and described current signal produces The signal receiving end of the crystal oscillating circuit of first portion, phase-locked loop circuit and described signal measurement apparatus is connected to described mixing electricity Road, described phase discriminator is connected to process circuit part.

Preferably, described slip read head has formed capacitor by metal level and metal band.

Preferably, the described additional temperature-compensation circuit of electric current range unit or use temperature compensating crystal oscillator (TCXO).

The beneficial effects of the utility model are: in the wire that conductivity is good, the spread speed of electric current can be close In electromagnetic wave.And its attenuation degree is far smaller than electromagnetic wave.Using current spread method to measure, overcoming electromagnetic wave signal can not Plain conductor transmits the problem measuring distance.

Accompanying drawing explanation

Fig. 1 is the schematic diagram that distance measured by this utility model electric current range unit；

Fig. 2 is the mathematical model that this utility model signal generator divides；

Fig. 3 is the Frequency Stability of this utility model voltage controlled oscillator phase-locked loop operation principle；

Fig. 4 is the schematic diagram of this utility model signal measurement apparatus；

Fig. 5 is the workflow diagram of this utility model electric current range unit；

Fig. 6 is the schematic diagram of this utility model phase discriminator.

Detailed description of the invention

Below in conjunction with the accompanying drawings this utility model is further elaborated:

Electric current range unit of the present utility model uses current signal to propagate the technology of range finding along metallic media.Such as Fig. 1 institute Show, distance to be measuredWherein v is the speed of current spread, t_2LThe time propagated on metallic media for electric current. Due toWherein, f is the frequency of current signal, and N is the number in current signal cycle, For phase contrast.Therefore,Wherein λ is the wavelength of current signal.This discussion scheme uses single-frequency source, this Time measure distance there is ambiguity, N cannot determine the most here, thus measure distance limit existIn the range of, i.e. work as N=0 Time, the distance of measurementIt is to say, in the case of known to the wavelength of current signal, it is only necessary to measure electric current The phase contrast that signal produces during metallic media is propagated just can draw this distance.Discussing part in principle, electric current is believed Number use single-frequency source.Known that survey chi is a length of by phase methodAs shown in the table.When distance measuring signal frequency is the highest, survey Chi length is the shortest, and precision is the highest.When distance measuring signal frequency reduces, surveying chi length increases, and precision reduces accordingly.So when measurement Distance, more than determining when substantially surveying chi length of precision, can select one or more auxiliary to survey chi (bigness scale chi) again.Last the most again Each surveys the measurement set of chi altogether.When being 1254.45m such as distance to be measured, can be selected for 3 survey chis, wherein= 1500m ,=15m ,=1.5m, measure respectively with them, can record 1254m, can record 4.4m, can record 0.45m.By three Person combines and just obtains measured value 1254.45m accurately.

Distance measuring signal frequency (HZ)	Survey chi length	Certainty of measurement (0.1% measurement error)
			100M	1.5m	1.5mm
10M	15m	15mm
			1M	150m	15cm
100K	1.5km	1.5m

Table 1

Electric current range unit of the present utility model includes: current signal produces part, signal measurement apparatus, mixing and phase demodulation Circuit part and process circuit part.Wherein current signal generating unit divides the crystal oscillating circuit and generation including producing the main signal that shakes The phase-locked loop circuit of local oscillation signal.Signal measurement apparatus includes signal sending end and signal receiving end, two gold being parallel to each other Belong to bar and a slidably read head being used for coupled signal on above-mentioned bonding jumper, the Location-Unknown of read head, wherein a gold Belonging to bar to be connected with signal sending end, another bonding jumper is connected with signal receiving end, and metallic media is for conduction and feedback signal. Mixing and phase discriminator part include mixting circuit and phase discriminator, and the master that signal generator divides shakes signal and phase-locked loop circuit Local oscillation signal is connected to mixting circuit.1, the signal of bonding jumper feedback in the local oscillation signal of phase-locked loop circuit and measurement apparatus connects To mixting circuit.2, after the radio-frequency component filtering two mixting circuit outfans, low frequency signal is connected respectively to phase demodulation electricity Two inputs on road.After phase discriminator, signal is input to follow-up signal and processes circuit.The signal of telecommunication is at range unit bonding jumper Can produce phase contrast in middle transmitting procedure, the phase contrast of the longest generation of distance of transmission is the biggest, i.e. this phase contrast with found range from Correlation.According to phase contrast and the relation of distance, process circuit measurement to phase contrast be converted into the distance of read head, And this distance is shown in display screen.

More specifically, as in figure 2 it is shown, current signal generating unit is divided includes crystal oscillating circuit, voltage comparator circuit and phaselocked loop Circuit, voltage comparator circuit is connected with crystal oscillating circuit and phase-locked loop circuit respectively.Current signal produces and partly produces two paths of signals: Main shake signal and local oscillation signal.The main signal that shakes is produced by the crystal oscillating circuit of high stable, and it provides clock letter for whole Circuits System Number.The main signal that shakes of crystal oscillating circuit output is to voltage comparator circuit, and master is shaken after signal intensity becomes standard block by voltage comparator circuit It is divided into three tunnels: a road is directly inputted to the transmitting terminal of range unit, as measuring signal；One tunnel input mixing and phase demodulation part Mixting circuit；Another road is input to phase-locked loop circuit, inputs as phase-locked loop circuit reference signal, and it is defeated to produce local oscillation signal Go out.The generation of this utility model signal source uses high stability crystal oscillator, directly as distance measuring signal, can eliminate the modulation of signal With the process such as demodulation, overcome that modulated signal is fainter and that easily disturbed by outside noise problem.

Phase-locked loop circuit is by frequency divider, phase discriminator PD, loop low pass filter LPF and voltage controlled oscillator VCO composition.Utilize Phase-locked loop circuit, it is possible to locking and lead the signal that shakes has the local oscillation signal of a difference frequency, such local oscillation signal and the main signal just tool that shakes There is the temperature drift characteristic of identical degree of stability and frequency so that difference frequency has good stability, improve the precision of measurement.

Phaselocked loop is used as during frequency synthesizer to need to use to frequency divider, convenient herein for narration, will ignore below point Frequently the effect of device.Phase discriminator PD in phaselocked loop is phase comparator, for comparator input signal and the output of voltage controlled oscillator The phase place of signal, and both phase signals are converted into voltage signal U_dIt is input to rear class.Phase discriminator is generally taken advantage of with simulation Musical instruments used in a Buddhist or Taoist mass completes, and the voltage of extraneous input signal is u_i(t)=U_i sin[ω_it+θ_i(t)], the output letter of voltage controlled oscillator Number voltage be u₀(t)=U₀sin[ω₀t+θ₀(t)], the signal voltage that phase discriminator (analog multiplier) exports is as follows:

$\begin{array}{c}{U}_d\left(t\right)=K_d{u}_i\left(t\right)u_o\left(t\right)\\ =K_d{U}_i\sin \[w_{i}t+{\mathrm{\θ}}_i\left(t\right)\]U_o\cos \[w_{o}t+{\mathrm{\θ}}_o\left(t\right)\]\\ =\frac{1}{2}{K}_d{U}_i{U}_o\sin \[w_{i}t+{\mathrm{\θ}}_i\left(t\right)+w_{o}t+{\mathrm{\θ}}_o\left(t\right)\]+\frac{1}{2}{K}_d{U}_i{U}_o\sin \{\[w_{i}t+{\mathrm{\θ}}_i\left(t\right)\]-\[w_{o}t+{\mathrm{\θ}}_o\left(t\right)\]\}\end{array}$

Low pass filter LPF phase discriminator high-frequency signal out filter out (i.e. above and frequency signal filter out), Remaining difference frequency component controls voltage U as the input of voltage controlled oscillator VCO_c, input controls voltage U_cExpression formula as follows:

$U_c\left(t\right)=\frac{1}{2}{K}_d{U}_i{U}_{0}sin\{\[({\mathrm{\ω}}_i-{\mathrm{\ω}}_0)t\]+\[{\mathrm{\θ}}_i\left(t\right)-{\mathrm{\θ}}_0\left(t\right)\]\}=U_{d}sin\{\[({\mathrm{\ω}}_i-{\mathrm{\ω}}_0)t\]+\[{\mathrm{\θ}}_i\left(t\right)-{\mathrm{\θ}}_0\left(t\right)\]\}$

In above-mentioned expression formula, ω_iAnd ω₀It is respectively input signal and the ringing angular frequency of output signal, θ_i(t) and θ₀T () is respectively input signal and the instantaneous phase of output signal.Relation according to phasor can obtain instantaneous frequency and instantaneous phase Relation be:I.e. θ (t)=∫ ω (t) dt+ θ_d0, therefore instantaneous phase difference is θ_d=(ω_i-ω₀)t+θ_i(t)-θ₀ T are differentiated in both sides by (), the relational expression that can obtain frequency difference isWhen above-mentioned relation formula During equal to zero, illustrating that phaselocked loop enters the state of PGC demodulation, now output and the frequency of input signal and phase place keep constant Constant state, applied signal voltage U_cT () is steady state value.As it is shown on figure 3, the expression formula of the Frequency Stability of voltage controlled oscillator is ω_u(t)=ω₀+K₀U_cFrequency of oscillation ω of (t), i.e. voltage controlled oscillator_uRinging angular frequency with output signal₀In for The heart, with applied signal voltage U_cThe change of (t) and change.Phaselocked loop enters " frequency pulling ", automatic trace trap input signal Frequency, make phaselocked loop enter the state of locking, and keep ω₀=ω_iState constant.

The distance measuring signal of signal range unit comes from the master that signal generator divides and shakes signal.Specifically, signal measurement portion Dividing and include two bonding jumpers being parallel to each other and a read head for coupled signal, this reading head location is unknown, can be the most sliding Dynamic, it is the slip read head of encoder, the metal level on described slip read head forms capacitor, coupling firing signal with metal band Return main circuit, draw the position of read head distance reference point by measuring the phase contrast relevant to length.By the coupling of capacitor Effect " is connected two bonding jumpers " to get up.Article one, bonding jumper meets the master that signal generator divides and shakes signal, another bonding jumper handle Distance measuring signal feeds back to the receiving terminal of range unit.Article two, bonding jumper is the bus on incremental linear encoder, and it was both made For the transmission medium of current signal, also as the survey chi of current signal, Capacitance Coupled is utilized to produce echo-signal.

The most directly measure distance the inconvenience of at 2, and when encoder high-speed motion, easily occur Error.Conventional electromagnetic wave signal is difficult in solid metal transmission, and metal is the good conductor of electric current.Bonding jumper is as electricity The propagation medium of flow measurement and survey chi, can transfer the measurement of distance to the phase difference measurement of current signal dexterously.

Current signal phase place in metallic media transmitting procedure can produce change, and phase place extent and range finding length Becoming positive correlation, if the master that signal generator divides shakes, signal isIf returning to connect after 2L distance The signal receiving circuit part isAs it was previously stated, the transmitting terminal of range unit and the letter of receiving terminal Number phase contrast isJust slip read head can be calculated relative to original position by trying to achieve this phase contrast Distance.

Mixing portion includes pre-amplification circuit, filter circuit, mixting circuit and band filter.Pre-amplification circuit handle After the signal received amplifies, the signal required for circuit taking-up after filtering.As it is shown in figure 5, obtained by after filter circuit frequency-selecting Signal beSet simultaneously the local oscillation signal after phaselocked loop is phase-locked as Local oscillation signal u_cWith signal u obtained after filter circuit frequency-selecting_rBeing mixed, the signal obtained is as follows:

With ω-ω_cBand filter the Section 1 high-frequency signal of above formula is filtered, i.e. can get low frequency distance measuring signal:

Master additionally shaking signal and local oscillation signal is mixed, the signal obtained is as follows:

In like manner, with band filter, the Section 1 high-frequency signal of above formula is filtered, i.e. can get low frequency reference signal:Low frequency distance measuring signal u'₁With low frequency reference signal u'₂Phase contrast beIt is to say, after high-frequency signal is filtered, phase contrast is constant, but the frequency measured reducesAgain, that is the cycle increases N times, and this is that phase demodulation below reduces difficulty, says measurement essence from another one angle Degree correspondingly improves N times.

Phase discriminator includes flip and flop generator, and timing pulse emitter, with door sum counter.With door respectively with bistable State trigger, timing pulse emitter sum counter connects.Phase discriminator receives mixting circuit two paths of signals out, uses number Word phase detecting method, joins flip and flop generator by this two paths of signals and carries out phase demodulation.As shown in Figure 6, reference signal e_rAnd range finding Signal e_mIt is coupled with S end and the R end of trigger.Reference signal e_rTrailing edge makes flip and flop generator set, and Q exports high level, Be equivalent to e_rDeclining as " enabling " signal with door of square wave.Through relative to phase contrastTime period after, distance measuring signal e_mInitially entering R end, its trailing edge makes trigger reset, that is Q end output low level.Be equivalent to e_mThe decline conduct of square wave " closing the door " signal with door.Therefore by with gate output terminal obtained by pulse width (i.e. the setting time of trigger) correspond to two The phase contrast of current signalDuring flip and flop generator set, open with door, the timing pulse of timing pulse emitter Cp, can close with door when flip and flop generator resets by entering enumerator with door, and counting stops.So enumerator institute The pulse number of accumulation is exactly the phase contrast of reference signal and distance measuring signal

Processing circuit part and include counting transducer and display, the number of pulses that counting transducer obtains enumerator turns Turn to measure distance, and shown by display.

If the pulse number making enumerator single phase demodulation gained is n, then haveWherein, f_CpFor markers The frequency of pulse Cp, f_rFor reference signal e_rFrequency, t_sTime for trigger set.For improving precision of phase discrimination, can use many Cycle synchronisation Phase Demodulation, then average.

In the wire that conductivity is good, the spread speed of electric current can be close to electromagnetic wave.And its attenuation degree is remote Much smaller than electromagnetic wave.So electricity consumption stream is injected in transfer wire, its feedback signal can be received, that is be to lead to The phase contrast crossing measurement signal measures the absolute displacement of read head indirectly.Use current spread method to measure, overcome electromagnetic wave letter Number can not transmit the problem measuring distance on plain conductor.

Can obtain in conjunction with said process, the electric current distance-finding method that electric current range unit of the present utility model uses includes:

Step one, signal generator is utilized to divide this master of generation to shake signal and local oscillation signal；

Step 2, signal that master is shaken are transmitted separately to mixing and the frequency mixer of phase demodulation part and signal range unit part Transmitting terminal；Signal slip read head on range unit being fed back to receiving terminal receives another frequency mixer；

Step 3, local oscillation signal is coupled with the input of above-mentioned two frequency mixer.

Local oscillation signal is carried out mixing with the main signal that shakes and obtains reference signal by step 4, mixting circuit part, local oscillator is believed Number with the signal of the propagation of read head feedback on bonding jumper carry out mixing obtain measure signal；

Step 5, after mixting circuit reference signal and measure signal HFS filter.

Step 6, phase discriminator is utilized to calculate reference signal and measure the phase contrast of signal, according to phase contrast and distance Relation measurement to phase contrast be converted into the distance of read head to be measured.

Step 7, when distance to be measured is bigger, survey chis with many and measure.Different frequency source compositions is measured not The survey chi of same distance, surveys chi for every and repeats the step one measurement process to step 7, finally each is surveyed the data set that chi measures Altogether, final distance value is obtained.

As the preferred scheme of one, utilize timing pulse that phase contrast is converted into count pulse in step 6, according to The number of count pulse calculates reference signal and measures the phase contrast of signal.

Electric current range unit of the present utility model utilizes current spread method to be to carry based on ranging phase method to measure distance Go out.Electric current can produce the skew of phase place in communication process, and the distance of propagation is the longest, and the skew of phase place is the biggest.Surveying Transmission signal away from device and reception signal are mixed, and after low pass filter filters high-frequency signal, are sent by measurement Signal and reception signal phase contrast between the two are just able to know that the length of distance to be measured.The most just can be measuring distance Length transition become measure current signal phase place.And by the method for current spread phase contrast, it is possible to two-way high-frequency signal Phase contrast is moved on two-way low frequency signal.Before and after difference frequency, the phase contrast of the low frequency signal obtained and directly measurement high frequency letter Number phase contrast be the same.But measure frequency to greatly reduce, say, that the cycle of measuring is elongated, correspondingly measures essence Degree greatly increases.

Embodiment described above, preferred embodiments the most of the present utility model, not limit enforcement model of the present utility model Enclose, therefore all equivalence changes done according to structure, feature and the principle described in this utility model claim or modification, all should It is included in this utility model patent claim.

Claims (3)

1. an electric current range unit, it is characterised in that described electric current range unit includes: current signal produces part, signal Measurement apparatus, mixing and phase discriminator part and process circuit part, described current signal generating unit is divided and is included producing main shaking The crystal oscillating circuit of signal and the phase-locked loop circuit of generation local oscillation signal, described signal measurement apparatus includes signal sending end and signal Receiving terminal, two bonding jumpers being parallel to each other and one on described bonding jumper for the slidably read head of coupled signal, its In a described bonding jumper be connected with described signal sending end, another described bonding jumper is connected with described signal receiving end, institute Stating mixing and include mixting circuit and phase discriminator with phase demodulation part, described current signal produces the crystal oscillating circuit of part, phaselocked loop The signal receiving end of circuit and described signal measurement apparatus is connected to described mixting circuit, and described phase discriminator is connected to process Circuit part.

2. electric current range unit as claimed in claim 1, it is characterised in that have on described slip read head by metal level and gold Belong to band and form capacitor.

3. electric current range unit as claimed in claim 1, it is characterised in that described electric current range unit additional temperature-compensating electricity Road or use temperature compensating crystal oscillator (TCXO).